Figure 2. Expression pattern analysis of the
lin-11 gene. GFP fluorescence of different-staged animals carrying integrated
lin-11-GFP reporter gene constructs are shown. The larval stages are indicated. The white arrow in the embryonic stages depicts an outgrowing axon from a neuronal cell body. Note that the GFP reporter construct does not contain the nuclear localization sequence of LIN-11; thus the axon and cell bodies fluoresce uniformly. Also note that because of differential planes of focus, not all neurons can be seen in every panel (e.g., in A, not all neurons in the lumbar ganglion are in the same plane of focus). A,C, F, Lateral view. B,D, E, Ventral and dorsal views. All animals shown (except those in E andF) carry an integrate dplin-11-ABCDE-GFP reporter gene construct (see Fig. 4). Note that in the early L2 animal in D, the VC motor neurons are not matured (they have not sent out their axonal projections) (Li and Chalfie, 1990), so that in the ventral cord, only the AVG, AVH/AVJ, andPVQ interneurons stain. The white triangles in D point to the left (PVQL) and right (AVG,AVH/AVJ, and PVQR) ventral cord tracts.E, F, Transgenic
plin-11-B-GFP animals, which display staining of theVC motor neurons and the vulva, are shown. The expression in the VC motor neurons begins at late larval stages after the postembryonic birth and axonal outgrowth of the VC neurons. Staining of tail neurons decreases in adulthood, whereas expression in the head neurons perdures. Expression in the vulval precursors cells is confined to the generation of thevulva during middle to late larval stages. Because the numbers of cells staining in these early larval stages does not appear to differ from the number of embryonically staining cells and because the onset of embryonic GFP staining correlates with the birth of these neurons, we conclude that the embryonic cells expressing
lin-11-GFP are exclusively neurons. An essentially similar expression pattern can be observed using a lacZ-reporter gene fusion (Freyd, 1991). The expression of
lin-11 in theAVG interneuron is considerably weaker than that in the other head neurons.